Surgical Robots Take Devices to Heart

As a boy, Dr. Greg Buckner dreamed of becoming a doctor and trying to save people’s lives. “My father was an engineering professor, and he talked me out of a medicine career by convincing me I could do a lot in medicine as an engineer,” he says. “I’ve always used that argument to guide my research.” By leading a team of NC State researchers that has patented two devices to assist with robotic heart surgeries, the associate professor of mechanical engineering is achieving his dream.

While most patients undergo open-heart surgery to repair a defective mitral valve, a growing number have a procedure that uses remote-controlled robotic instruments—slender mechanical arms inserted through small openings in the ribs—to cause less pain and tissue trauma. Buckner’s interest in the technology led him to observe robotic heart surgeries at East Carolina University—a pioneer in the field—to see how he could help improve the technology.

Although it reduces trauma, using robotic instruments adds about an hour to the valve-repair surgery, which increases the risk of health complications for the patient, disqualifying many from the procedure. Buckner assembled a team that included Dr. Bryan Laffitte, associate professor of industrial design, and Dr. Denis Cormier, associate professor of industrial engineering, to develop devices to shorten the robotic surgery.

One time-consuming aspect is securing a band around the valve to help it maintain its shape, a process that involves tying dozens of knots in sutures. “It’s like tying your shoelaces with tweezers,” Buckner says. Laffitte and his design students dreamed up a device with a rotating disc that allows knots to be tied without having to let go of the suture and grasp it again. Cormier then used his rapid prototyping system to manufacture the device — a dime-sized plastic cartridge that snaps onto the end of the robotic instrument to tie knots. The NC State team also developed a retractor to expand the interior of the heart enough for surgeons to see what they’re doing and provide more space for the robotic instruments. Surgeons currently have to work a metal plate through the body and prop it up inside the heart. The NC State researchers created a metal rod that the robotic scope can slide into the heart, where four motorized wire wings can quickly unfold to open up the surgical field.

Design students dreamed up a device that allows knots to be tied without having to let go of the suture and grasp it again.

Buckner is lining up clinical trials for the inventions. “These devices have the potential to significantly reduce surgical times,” says Dr. Richard Cook, a cardiothoracic surgeon at the University of British Columbia who helped test them during his fellowship at ECU. “They could make robotically-assisted heart surgery and faster recovery available to many more patients.”

An NC State team has designed a plastic cartridge with a rotating disc, below, allowing robotic instruments to tie knots in sutures more quickly. A rod with retractable wire wings, right, also devised by the team, expands the interior of the heart to bring the surgical field into better view.